Suction pile installation method and suction pile for use in said method

Abstract

Suction pile installation method comprising the steps of lowering a suction pile to the sea bed, while keeping a top end substantially closed providing openings in the suction pile near a lower end, the interior of the suction pile being in open fluid communication with the exterior via the openings, dropping the pile onto the sea bed, while allowing air to escape from the pile via said openings, and allowing the suction pile to penetrate into the sea bed driven substantially by its weight over such a distance that the openings become closed from the exterior, and pumping air from the suction pile for driving the pile further into the sea bed.

1. A suction pile installation method comprising the steps of:
 lowering a suction pile ( 10 ) to the sea bed, the suction pile having a top surface ( 11 ), a substantially cylindrical side surface ( 15 ) and a bottom surface ( 18 ) which is at least partially open, 
 keeping the interior of the suction pile in open fluid communication with the exterior at least via the bottom surface, dropping the pile onto the sea bed ( 19 ), characterized in that the method comprises: 
 allowing fluid to escape from the pile via at least one opening ( 16 ,  17 ) in a lower half of the side surface ( 15 ) for reducing the pressure inside the suction pile upon contact of the suction pile with the sea bed, and 
 allowing the suction pile to penetrate into the sea bed over such a distance that the at least one opening ( 16 ,  17 ) in the side surface becomes closed off from the exterior by the soil, and 
 pumping air from the suction pile from an air connection ( 12 ) situated in an upper half of the suction pile for driving the pile further into the sea bed. 
 
   
   
     2. The method according to  claim 1 , wherein the pile ( 10 ) is driven into the soil over the distance that the at least one opening ( 16 ,  17 ) becomes blocked substantially by its own weight. 
   
   
     3. The method according to  claim 2 , wherein the pile ( 10 ) is connected to a removable disconnectable pump skid which is activated by a ROV. 
   
   
     4. The method according to  claim 2 , wherein the pile ( 10 ) is connected via an air hose ( 13 ) to a surface vessel ( 14 ). 
   
   
     5. The method according to  claim 1 , wherein the pile ( 10 ) is connected to a removable disconnectable pump skid which is activated by a ROV. 
   
   
     6. The method according to  claim 5 , wherein the pile ( 10 ) is connected via an air hose ( 13 ) to a surface vessel ( 14 ). 
   
   
     7. The method according to  claim 1 , wherein the pile ( 10 ) is connected via an air hose ( 13 ) to a surface vessel ( 14 ). 
   
   
     8. The method according to  claim 1 , wherein the suction pile ( 10 ) is applied from a surface vessel ( 14 ) and is attached to said vessel via an elongate member ( 13 ) without the use of a tension compensation device. 
   
   
     9. A suction pile ( 10 ) comprising:
 a top surface ( 11 ), 
 a substantially cylindrical side surface ( 15 ), 
 a bottom surface ( 18 ) which is at least partially open, and 
 an air connection ( 12 ) situated in an upper half of the suction pile, 
 the suction pile comprises in a lower half (L) of the side surface at least one opening ( 16 ,  17 ) that allows fluid to escape from the pile to reduce pressure inside the suction pile upon contact of the suction pile with the sea bed. 
 
   
   
     10. A suction pile ( 10 ) according to  claim 9 , the suction pile comprising in an upper halve a valve ( 12 ) for a relatively slow rate of fluid transfer, no fluid venting means being present in the upper halve for fluid transfer from the pile upon entering the soil.